//你好,世界
// console.log('Hello World');

function greet(person: string, date: Date) {
    console.log(`Hello ${person},today is ${date}`);
}

greet('小千', new Date())

// let msg = "hello there!";
// msg = 'hello world';
// msg = 100


// let surname: string = undefined;
// let age: number = null;